If there’s one thing I’ve learned over the last decade-plus of blogging about medicine and alternative medicine, it’s that any time there is an outbreak or pandemic of infectious disease, there will inevitably follow major conspiracy theories about it. I saw it during the H1N1 pandemic in the 2009-2010 influenza season, the Ebola outbreak in late 2014, and the Disneyland measles outbreak last year, when cranks of many stripes claimed that either the outbreaks themselves were due to conspiracies (usually, but not limited to, conspiracies to promote the “depopulation” vaccination agenda of—who else?—Bill Gates) or that nefarious forces were seizing on the outbreak to take away our freedom. The second thing I’ve learned is that inevitably people will try to impose their ideology on to the disease and try to use outbreaks to push their own ideological agenda. Indeed, the Ebola outbreak, for example, was rapidly seized on by politicians to promote quarantines and to halt immigration from the affected countries. This year, the biggest infectious disease-related story thus far is the Zika virus outbreak in Brazil that has been linked to microcephaly and other birth defects, and it’s a case of the same stuff, different year.
The Zika virus is a mosquito-borne flavivirus related to dengue virus and transmitted primarily by Aedes aegypti mosquitoes. On the surface, this virus would appear to be relatively benign, with 80% of those infected by it remaining asymptomatic, while the other 20% suffer from what is usually a self-limited, relatively mild illness characterized by fever, rash, arthralgias (joint aches), and conjunctivitis. In the grand scheme of things, after decades of being endemic in many tropical areas Zika virus infection probably didn’t seem so bad and didn’t appear to be much of a public health priority in the regions where Aedes aegypti mosquitoes live, mainly tropical regions in South and Central America, Africa, southeast Asia, and the Pacific islands. Then came the evidence that prenatal infection might cause microcephaly, and everything changed. Not surprisingly, conspiracy theories galore arose with social media speed, as did the ideologically motivated overselling of proposed solutions, such as bringing back DDT to combat the mosquito carrying the disease.